class_docstr: class for handling plain text corpus
      
code: def __init__(self):
      self.documents = None
  
file_path: underthesea/underthesea/corpus/plaintext_corpus.py
imports: from underthesea.corpus import Corpus, Document
  from os.path import join
  from os import listdir, mkdir
  from underthesea.feature_engineering.unicode import UnicodeTransformer
  from underthesea.util.file_io import write
  import io
label_desc: Use image node_id 1 to create a new PlainTextCorpus object from inherited base classes: Corpus with example: obj = PlainTextCorpus()